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1) Ta có: \(3\left(x-1\right)-5\left(x-2\right)=4\left(x+1\right)\)
\(\Leftrightarrow3x-5-5x+10-4x-4=0\)
\(\Leftrightarrow-6x+1=0\)
\(\Leftrightarrow-6x=-1\)
hay \(x=\dfrac{1}{6}\)
2) Ta có: \(-2\left(x-2\right)-4\left(x+1\right)=-3\left(x+3\right)\)
\(\Leftrightarrow-2x+4-4x-4+3x+9=0\)
\(\Leftrightarrow-3x=-9\)
hay x=3
3) Ta có: \(3x^2+2x=0\)
\(\Leftrightarrow x\left(3x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{2}{3}\end{matrix}\right.\)
4) Ta có: \(x^2-5x=0\)
\(\Leftrightarrow x\left(x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\end{matrix}\right.\)
5) Ta có: \(\left(2x-3\right)^2=36\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-3=6\\2x-3=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=9\\2x=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)
6) Ta có: \(\left(5x-1\right)^3=125\)
\(\Leftrightarrow5x-1=5\)
\(\Leftrightarrow5x=6\)
hay \(x=\dfrac{6}{5}\)
7) Ta có: \(3^{x+1}=27\)
\(\Leftrightarrow x+1=3\)
hay x=2
a: =>x/27+1=-2/3
=>x/27=-5/3
=>x=-45
b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)
=>x=221/50
c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)
=>x=1/15-2/3=1/15-10/15=-9/15=-3/5
d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)
=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)
=>x=-37/24
e: =>-3/7x=84/45
=>x=-196/45
f: =>11/10x=-2/3
=>x=-20/33
a) x+x+x + 91 = -2
3x+91=-2
3x=-93
x=-31
b) -125 - (3x+1) = -2 . -27
-125-(3x+1)=54
-3x=54+126
-3x=180
x=-60
c) |5x +1| =14
\(\Leftrightarrow\orbr{\begin{cases}5x+1=14\\5x+1=-14\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)
P/s tham khảo nha
a) \(x+x+x+91=-2\)
\(3x=-93\)
\(x=-31\)
vậy \(x=-31\)
b) \(-125-\left(3x+1\right)=\left(-2\right).\left(-27\right)\)
\(-125-3x-1=54\)
\(-3x=54+1+125\)
\(-3x=180\)
\(x=-60\)
vậy \(x=-60\)
c) \(\left|5x+1\right|=14\)
\(\Rightarrow\orbr{\begin{cases}5x+1=14\\5x+1=-14\end{cases}}\Rightarrow\orbr{\begin{cases}5x=13\\5x=-15\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)
vậy \(\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)
P/S: fan Khởi My ^_^
x + x + x + 91 = -2
x + x + x = -2 - 91
x + x + x = -93
3x = -93
x = -93 : 3
x = -31
-152 - (3x + 1) = (-2) . (-27)
-152 - (3x + 1) = 54
3x + 1 = -152 - 54
3x + 1 = -206
3x = -206 - 1
3x = -207
x = -207 : 3
x = -69
|5x + 1| = 11
5x + 1 = 11 hay 5x + 1 = -11
5x = 11 - 1 hay 5x = -11 - 1
5x = 10 hay 5x = -12
x = 10 : 5 hay x = -12 : 5
x = 2 hay x = -2,4
Mà x ∈ Z
x = 2
a) 9x-1=32
( 32 )x-1 = 32
32x-2 = 32
⇒ 2x-2 = 2
2x = 2+2
2x = 4
x = 4 : 2
x = 2
b) 5x+2=625
5x+2= 54
⇒ x+2 = 4
x = 4-2
x = 2
c) 2x: 25= 2
2x:25 = 21
2x = 21 . 25
2x = 26
⇒ x = 6
d) 3x:27=3
3x:33 = 31
3x = 31.33
3x = 34
⇒ x = 4
a) Ta có: \(9^{x-1}=3^2\)
\(\Leftrightarrow3^{2x-2}=3^2\)
\(\Leftrightarrow2x-2=2\)
\(\Leftrightarrow2x=4\)
hay x=2
Vậy: x=2
b) Ta có: \(5^{x+2}=625\)
\(\Leftrightarrow5^{x+2}=5^4\)
\(\Leftrightarrow x+2=4\)
hay x=2
Vậy: x=2
c) Ta có: \(2^x:2^5=2\)
\(\Leftrightarrow2^{x-5}=2^1\)
\(\Leftrightarrow x-5=1\)
hay x=6
Vậy: x=6
d) Ta có: \(3^x:27=3\)
\(\Leftrightarrow3^x:3^3=3\)
\(\Leftrightarrow3^{x-3}=3^1\)
\(\Leftrightarrow x-3=1\)
hay x=4
Vậy: x=4
1: Ta có: 7x+6(3-x)=27-20+73
\(\Leftrightarrow7x+18-6x=80\)
\(\Leftrightarrow x=80-18=62\)
Vậy: x=62
2: Ta có: \(6x-5\left(x-7\right)=\left(27-514\right)-486-73\)
\(\Leftrightarrow6x-5x+35=27-514-486-73\)
\(\Leftrightarrow x+35=-1046\)
\(\Leftrightarrow x=-1081\)
Vậy: x=-1081
Mấy bài thực hiện phép tính bn tự làm nha
3.|x+4|-2.(x-1)=7-2x
3.|x-4|-2x-2=7-2x
=>2.|x-4| =7-2x+2x+2
=>2.|x-4| =9-4x
=>|x-4| =4,5-2x
=>x-4=4,5-2x hoặc x-4=-4,5+2x
2+2x=4,5+4 4,5-4=2x-2
3x =8,5 0,5 =x
x =8,5:3
x =2,833
Vậy x\(\in\){2,833;0,5}
Phần còn lại bn làm tương tự nha
Chúc bn học tốt
a) Ta có: \(\dfrac{-3}{5}x+\dfrac{-7}{4}=\dfrac{3}{10}\)
\(\Leftrightarrow\dfrac{-3}{5}x=\dfrac{3}{10}+\dfrac{7}{4}=\dfrac{41}{20}\)
\(\Leftrightarrow x=\dfrac{41}{20}:\dfrac{-3}{5}=\dfrac{41}{20}\cdot\dfrac{-5}{3}\)
hay \(x=-\dfrac{41}{12}\)
Vậy: \(x=-\dfrac{41}{12}\)
=> \(5^{x-1}\)= 27 - 2
=> \(5^{x-1}\)= 25
=> x - 1 = 2
=> x = 2 + 1 = 3
Ta có: 27 - 5x - 1 = 2.
=> 5x - 1 = 25.
5x - 1 = 52.
=> x - 1 = 2
x = 3.